This invention relates to the removal of one or more materials from a medium, and more particularly, to a sorption method and element for effecting such removal.
The prior art has long been aware of, and has utilized, the sorbent properties of certain materials to effect the removal of matter from a liquid or gaseous medium. The myriad uses of such sorbent materials include such divergent processes as the removal of undesirable impurities from a liquid system and the removal of a desired solid specie or species from a liquid system containing that specie in a dissolved or dispersed state. Typical sorbent materials include charcoal and ion-exchange resins which display a marked affinity for a wide variety of dissolved or dispersed solids.
Such sorbent materials have been utilized in various analytical techniques where it is desired to quantitatively remove one or more solid materials from liquid system. A specific example of such utilization lies in the field of drug analysis, i.e., the analysis of a biological fluid system such as blood or urine to determine both the type and quantity of whatever drugs may be contained therein. In such methods, urine. for example, is passed through or otherwise contacted with a sorbent material capable of removing certain drugs from the liquid system. The sorbent is then processed in a series of washings to result in an effluent of the removed drug or drugs. This effluent is then analyzed, for example by chromatographic techniques, to determine the type and quantitative amount of drugs contained in the system.
Additional examples of such analytical techniques include the determination of the quantity and type of pollutants in air samples.
As is apparent from the foregoing description, these analytical techniques, to be effective, require a near quantitative removal of the solid matter from the liquid or gaseous system, as well as the eventual near quantitative removal of the solid matter from the sorbent material. Such requirements have proven to be exceptionally difficult to meet and, indeed, are often counter-productive. For example, it is generally found that finely-divided sorbents, due to the attendant exposure of a large surface area, more effectively sorb solid matter from liquid systems. Yet this same desirable attribute significantly hampers the ability to quantitatively remove the solid matter, since the finely divided sorbent often disperses into and is carried away with the liquid system or contaminates the desired effluent containing the solid matter. In the specific example of drug analysis, the presence of any such sorbent material in the drug solution subjected to chromatographic analysis results in possible incorrect quantitative readings and "background" interference with the time and size of the peaks associated with the particular drug.
Accordingly, many prior art techniques for enhancing the effectiveness of sorptive materials are not applicable to analytical techniques designed to quantitatively recover matter removed by the sorbent.
It is an object of this invention to provide a process for the quantitative sorption of matter from a liquid or gaseous system.
Another object of this invention is to provide a process for the quantitative sorption of solid matter from a liquid system and the subsequent quantitative removal of the solid matter from the sorbent material.
Yet another object of this invention is the provision of a sorbent material capable of quantitatively sorbing solid matter from a liquid system and of quantitatively yielding such sorbed solid matter.
A more specific object of this invention is the provision of a process and sorptive element for the quantitative analysis of durgs contained in a biological liquid system.
Another object of this invention is the provision of a process for removing gaseous matter from a liquid system.
A further object of this invention is the provision of a process for removing solid matter from a gaseous medium.
An additional object of this invention is to provide an apparatus useful in the sorption of solid material from small liquid samples.